In the manufacture of pressure sensitive adhesive labels, typically a liner sheet and a paper sheet are merged together during construction, and then are die cut, or otherwise formed into labels. The adhesive is usually applied to a liner sheet of silicone release material or the like, and then transfers to the paper sheet after the sheets are merged. Various forms of this basic technique are used to produce all sorts of labels, including products known as "integrated labels", and shown in U.S. Pat. No. 5,129,682 (the disclosure of which is hereby incorporated by reference herein).
According to the present invention, a method of manufacturing labels of a wide variety of types, including integrated labels, is provided which is simpler than prior art techniques, and also requires the utilization of only a single web of paper to construct the labels. The method of the invention is particularly simple and straight forward for the manufacture of integrated labels. While the technique described in U.S. Pat. No. 5,129,682 in which transfer tape is used to form the integrated label is widely accepted commercially, a separate supply of transfer tape, or web of silicone release material which is coated to produce transfer tape, is required. The method of the invention provides a more efficient in-line method of making integrated labels and does away with the separate web, only one web being necessary. Thus the invention results in a cost saving and a time savings compared to the process in U.S. Pat. No. 5,129,682. Similar advantages are also present compared to other techniques for making other types of labels.
The invention also relates to a unique intermediate for making labels, including integrated labels. The intermediate according to the invention has a unique construction, and facilitates the ready, efficient, and simple manufacture of labels, including integrated labels.
According to one aspect of the present a method of making a label having a first ply with a first printable face and a second pressure sensitive adhesive covered face, and a second ply with a first face and a second release material covered face, the second faces of the plies in face-to-face engagement with each other, using a web of label material having first and second faces, is provided. The method comprises the following steps: (a) Applying pressure sensitive adhesive in a first strip on the second face of the web of label material. (b) Applying release material in a second strip on the second face of the web of label material so that the second strip is adjacent, but spaced from, the first strip and substantially parallel thereto, a line of demarcation provided between the first and second strips. After steps (a) and (b): (c) folding the label material about the line of demarcation so that the first and second strips come into face-to-face contact with each other; and (d) acting on the label material from step (c) so that individual labels are formed from the label material, each label having a first ply with a first printable face corresponding to the first face of the web from which it is ultimately formed, and a second pressure sensitive adhesive covered face corresponding to the second face of the web from which it is ultimately formed, and a second ply with a first face corresponding to the first face of the web from which it is ultimately formed and a second release material covered face corresponding to the second face of the web from which it is ultimately formed, the second faces of the plies in face-to-face engagement with each other.
Step (a) is typically practiced by applying hot melt adhesive with an extrusion die. The hot melt adhesive may be rendered detacky when directly exposed to a sufficient does of electromagnetic radiation (e.g. ultraviolet light), as more fully described in copending application Ser. No. 08/368,963 filed Jan. 5, 1995.
Step (b) is typically practiced by pattern coating a silicone release material, such as an ultraviolet light (UV) curable, or Electron Beam (E) curable, silicone release material, and curing takes place before step (c). The line of demarcation typically is at least about 1 mm in width, preferably about 1-25 mm. If UV curing of the silicone release material is practiced the adhesive is applied after the curing so as not to expose the adhesive to UV radiation.
Step (c) may be practiced by plow folding while the label material is in web form, and as it moves continuously in a given direction. Alternatively, the web may be cut into sheets, and plow folded before or after cut into sheets, and optionally otherwise folded.
Step (d) is typically practiced by die cutting, slitting, or both die cutting and slitting. Slitting takes place along the line of demarcation, typically after folding, and die cutting actually cuts the labels from the folded-over web, and the matrix material can be removed after die cutting as shown per se in U.S. Pat. No. 5,129,682. Die cutting and slitting also preferably take place while the web is moving.
During the practice of all of steps (a)-(d) the web can be continuously moving in a first direction. All of these method steps can be practiced on a Webtron press, using conventional cutting cylinders, plow folders, extrusion dies, and the like to perform the various operations. Conventional pattern coating, or other extrusion application, equipment is precise enough to provide a line of demarcation, and the width of the line may vary about 1 mm without any adverse affect, therefore no special efforts need be made to insure a line of demarcation. When the web includes tractor feed strips, the method comprises the further step (e) of cutting off the tractor feed strips before practicing step (c). While the method can be used to produce a wide variety of labels, it is particularly useful for producing integrated labels.
The method may also comprise the further step (e) of applying (e.g. pattern coating) a third strip of pressure sensitive adhesive on the web second face on the opposite side of the second strip from the first strip to provide a second line of demarcation between the second and third strip--in which case step (c) is also practiced to fold the label material about the second line of demarcation so that opposite edges of label material will be adjacent and parallel to each other after step (c).
According to another aspect of the present invention, a unique intermediate for a label is also provided. The intermediate includes: A web of paper having first and second faces and first and second side edges. A strip of pressure sensitive adhesive on the second face and adjacent the first edge, having a first width (typically at least wide enough to provide the adhesive backing for a conventional full size label, e.g. at least about one inch); and a strip of silicone release material on the second face and adjacent and parallel to the strip of pressure sensitive adhesive (and also at least about one inch wide) and separated from the pressure sensitive adhesive material strip by a line of demarcation about 1-25 mm wide. The strip of silicone release material may also have substantially the first width, and it may be adjacent the second edge of the web, or spaced at least three inches from the second edge of the web.
It is the primary object of the present invention to provide a simple and efficient method of producing labels, particularly integrated labels, and a unique intermediate therefor. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.